470 to inline 6 swap

[hadaveha]

I have a chance to buy a freshly rebuilt mercruiser 165 inline 6 for a very good price, it comes with the manifolds gimble everything but the outdrive, so just how big is the bear I am about to wrestle, I know I have got to address the motor mounts, but my boat is aluminum so that should be a lot simpler to deal with, the motor is a1972 my 470 is a 1984, I do have the alpha 1 outdrive, will I have to find me a older MR outdrive also what about my wiring harness will it have to be spliced any chance of a plug and play.

 

[Bondo]

I have a chance to buy a freshly rebuilt mercruiser 165 inline 6 for a very good price, it comes with the manifolds gimble everything but the outdrive, so just how big is the bear I am about to wrestle, I know I have got to address the motor mounts, but my boat is aluminum so that should be a lot simpler to deal with, the motor is a1972 my 470 is a 1984, I do have the alpha 1 outdrive, will I have to find me a older MR outdrive also what about my wiring harness will it have to be spliced any chance of a plug and play.

Ayuh,... Yer 1st issue is the flywheel cover rear motor mounts are different widths,...

Maybe,... you can use the inner transom plate from the '72 on yer '84 transom assembly, but I'm not sure of that,....
If that works, I believe you'll need the shorter outdrive input shaft to use yer Alpha drive,...

The wirin' cannon plug oughta be plug, 'n play,...
The exhaust attachments will also probably be tricky,...

 

[hadaveha]

would it be best to just swap over to the 165 gimble housing I am replacing my transom anyway and find a older outdrive

 

[Bondo]

would it be best to just swap over to the 165 gimble housing I am replacing my transom anyway and find a older outdrive

Ayuh,.... Yer drive will run on either transom, with the shorter input shaft that used to be on the ole MC-1s, for GM In-line motors,...
The Alpha 1s, 'n MC-1s interchange, at the bellhousin' connection,...

I'd look at the condition of each transom assembly before makin' that choice,....
The MC-1 might be the old splined tiller, insteada the square pin tiller connection,...

 

[bobsquatch]

The 470 was a descent motor when upgraded. Good economy/reliability sans the charging system and ignition. If I was going to significantly modify my vessel for a re power I would go diesel.

 

[hadaveha]

I'm not a anti 470 guy. I'm just super familiar with the straight 6 engine. I just grew up with them and feel like I can work and maintain it much better

 

[achris]

To change the transom assembly over you are going to need to fill 2 of the holes and drill new ones. You're also going to have a nasty gap for a few inches long down each side which will also need to be filled. And no, you can't use the 84 outer with the 72 inner either.

Why not just fix up the 470?

 

[hadaveha]

I think I'm going to drop kick that idea It's funny I'm sure a lot of guys have been painted into this corner of. If I can get a cpl years out of the 470 without having to spend a bunch on it, or wait until I have the funds to get a really nice 4.3 set up.

 

[Bondo]

I think I'm going to drop kick that idea It's funny I'm sure a lot of guys have been painted into this corner of. If I can get a cpl years out of the 470 without having to spend a bunch on it, or wait until I have the funds to get a really nice 4.3 set up.

Ayuh,.... The 4.3l is Closer to a plug, 'n play,.... still re-engineerin' to do though,...

 

[stonyloam]

Yeah if you can work on a Chevy six, you should have no trouble with the MCM 4. Two things to look at: do a compression check to chech the health of the head gasket, and if you can get it running, check for a coolant leak from the weep hole in the lower starboard side of the engine waterump. Replacing a head gasket or water pump seals are one day jobs. If you can get it running well, you might like it.
P.S. Change the outdrive impeller, overheating is very bad for 470's.

 

[hadaveha]

ya I changed the OD impeller already, I went ahead and changed the oil, the oil was used but looked to be free of any water, I have to replace the starter before I can do a compression check, man that starter is a bast--- to get off, it does have the 4 inch heat exchanger, and it has the alternator, I have a petronix kit and a flame thrower coil for it, I also have a aluminum manifold off of a newer 470 I am going to put on my 1984, I have orderd a new thermastate 160degree, if Im going to do it I am going to jump in with both feet

 

[stonyloam]

Yeah that starter can be a pain to get out past the exchanger. Check out e bay for a new one.

 

[hadaveha]

I got one orderd tonight, it's the bottom nut you can only get a open end wrench on it and I can get no force on it at all Its a knuckle buster for sure